Rotary knife fixture for cutting spiral, textured potato pieces

ABSTRACT

A rotary knife fixture for cutting vegetable products such as raw potatoes into spiral shapes. The knife fixture includes a ring-shaped blade holder driven rotatably within a hydraulic product flow path. The blade holder includes at least one cutting blade, wherein the blade is twisted from a generally longitudinally aligned center axis outwardly in opposite circumferential directions with a sharpened leading edge set at a desired pitch angle. By controlling the pitch angle of the blade in relation to the blade rotational speed and velocity at which the potato travels along the hydraulic flow path, the resultant spiral cut shape is selected. By using multiple cutting blades at known axially spaced positions and selecting the angular position of each cutting blade in succession, the number of spiral shapes cut from each potato is selected. The blades can have a nontextured straight-cut edge, or a textured crinkle-cut edge, or a combination.

CROSS-REFENENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/712,857, filed on May 14, 2015 and entitled “Rotary Knife Fixture forCutting Spiral, Textured Potato Pieces,” which is a continuation of U.S.patent application Ser. No. 13/647,319, filed on Oct. 8, 2012 andentitled “Rotary Knife Fixture for Cutting Spiral, Textured PotatoPieces,” now U.S. Pat. No. 9,089,987, which claims the benefit of U.S.Provisional Patent Application Ser. No. 61/661,278, filed on Jun. 18,2012 and entitled “Rotary Knife Fixture for Cutting Spiral, TexturedPotato Pieces,” and claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/546,035 filed on Oct. 11, 2011 and entitled“Rotary Knife Fixture for Cutting Spiral Potato Pieces,” the contents ofall of which are incorporated herein by reference in their entireties.

FIELD OF THE DISCLOSURE

This invention relates generally to devices and methods for cutting foodproducts, such as vegetable products, and particularly such as rawpotatoes and the like, into spiral or helical shaped pieces, whose cutsurfaces may be patterned by the design of knife blades, such as tocreate textured “crinkle-cut” spiral or helical pieces.

BACKGROUND

Production cutting systems and related knife fixtures are useful forcutting vegetable products such as raw potatoes into spiral or helicalshaped pieces, preparatory to further production processing steps suchas blanching and parfrying. In this regard, one typical productionsystem comprises a hydraulic cutting system wherein a so-called waterknife fixture is mounted along the length of an elongated tubularconduit. A pumping device is provided to entrain the vegetable productsuch as raw potatoes within a propelling water flume for cuttingengagement with knife blades of the water knife fixture. The vegetableproduct is pumped one at a time in single file succession into andthrough the water conduit with a velocity and sufficient kinetic energyto carry the vegetable product through a relatively complex knifefixture which includes at least one rotary cutting blade for severingthe product into a plurality of smaller pieces of generally spiral orhelical shape. The cut pieces are then carried further through adischarge conduit for appropriate subsequent processing, includingcooking or blanching, parfrying, freezing and packaging steps, forsubsequent finish processing and serving to customers as loops, twirls,curly fries, etc.

Examples of such hydraulic cutting systems and related rotary knifefixtures are found in U.S. Pat. Nos. 5,168,784; 5,179,881; 5,277,546;5,343,791; 5,394,780; 5,394,793; 5,473,967; 5,992,287; and Re. 38,149,all of which are incorporated by reference herein. Persons skilled inthe art will recognize and appreciate that mechanical production feedsystems may be employed in lieu of hydraulic feed systems, as describedin U.S. Pat. Nos. 5,097,735; 5,167,177; 5,167,178; and 5,293,803, whichare also incorporated by reference herein.

The present invention is directed to an improved rotary knife fixtureand related cutting blades for cutting raw vegetable products, such aspotatoes, into spiral shaped pieces that may or may not have texturedcut surfaces, such as crinkles, waves, or other designs.

SUMMARY

In accordance with the invention, a rotary knife fixture is provided forcutting vegetable products such as raw potatoes into spiral shapes. Theknife fixture comprises a circular or ring-shaped blade holder adaptedto be rotatably driven at a selected rotational speed within a hydraulicproduct flow path. The blade holder carries at least one cutting bladerotated therewith, wherein the blade is twisted from a generallylongitudinally aligned center axis outwardly in opposite radialdirections with a sharpened leading edge set at a desired pitch angle.By controlling the pitch of the blade in relation to the rotationalspeed of the blade and the velocity at which the potato travels alongthe hydraulic flow path, the resultant spiral cut shape is selected. Byusing multiple cutting blades at known axially spaced positions andselecting the angular position of each cutting blade in succession, thenumber of spiral shapes cut from each potato is also selected.

In one preferred form, the ring-shaped blade holder of the rotary knifefixture is rotatably driven within a vegetable product flow path, suchas along a hydraulic flow conduit having raw vegetables such as potatoescarried in single file there through. The blade holder supports at leastone cutting blade which is twisted from a generally longitudinallyaligned center axis outwardly in opposite radial directions, anddefining a pair of sharpened cutting edges presented in oppositecircumferential directions. Each half of the cutting blade is set at aselected pitch angle which varies according to specific radial position,per the formula:

Pitch Angle=ArcTan (2×Pi×Radius/Pitch Length)  (1)

For a blade diameter equal to 4 inches (radius=2 inches), and a pitchlength equal to 3 inches, each cutting blade is anchored at its outeredge on the associated ring-shaped blade holder at an angle of about76.6°. However, note that the specific pitch angle will vary accordingto radial position along the blade and the pitch length.

In use, the single cutting blade is rotatably driven, in a preferredform, at a rotational speed of about 6,000 revolutions per minute (rpm),to cut each potato traveling along the hydraulic flow conduit at avelocity of about 25 feet per second (fps) into a pair of generallyspiral shaped pieces. With a pitch length of about 3 inches potatotravel per cutting blade revolution, this results in substantiallyoptimum cutting of each potato. In one embodiment, a cutting blade isrotatably driven at a rotational speed anywhere from about 4,000 rpm to8,000 rpm. In one embodiment, a cutting blade is rotatably driven at arotational speed anywhere from about 4,000 rpm, about 5,000 rpm, about6,000 rpm, about 7,000 rpm, or about 8,000 rpm, or at revolutionsgreater than 8,000 rpm.

When more than one cutting blade is used, each of the cutting blades maybe physically supported in a stack of ring-shaped blade holders having aknown axial dimension such as about 0.5 inch per blade holder, with themultiple blade holders being fixed for rotation together. With thisconfiguration, the angle Θ (theta) separating each of the supportedcutting blades in succession is given by the formula:

Θ=T/P (axial dimension of each blade holder/pitch length)×360°+360°/N(number of cut pieces).  (2)

Following this formula, when two cutting blades are used, each carriedby a 0.5 inch thick ring-shaped blade holder (thickness=T), with a pitchlength (pitch=P) of 3 inches, a total of four spiral pieces are cut fromeach product, and the second cutting blade is rotationally set to lagthe first cutting blade by 150°. Similarly, where three cutting bladesare used, each product is cut into a total of six spiral pieces, and thesecond blade is oriented to lag the first blade by 120°, and the thirdblade is oriented to lag the second by an additional 120°, or a totallag from the first blade of about 240°. And, where four cutting bladesare used, each product is cut into a total of eight spiral pieces, andthe four blades are oriented respectively to lag the immediatelypreceding blade by about 105°.

Accordingly, the present invention encompasses a configuration ofmultiple blades to produce 2, 4, 6, 8, or more spiral pieces perproduct. In addition to even numbers of spiral pieces cut per product,the present invention encompasses a configuration of blades that produce3, 5, 7, 9 or more spiral pieces per product. An example of such aspiral piece is shown in D640,036, which is incorporated herein byreference.

A further aspect of the present invention is a cutting blade designed tohave a textured or “crinkled” surface edge so that when it cuts theproduct, the exposed cut surface is similarly textured or crinkled.Accordingly, in one embodiment crinkle-cut spiral pieces of product canbe produced using the inventive blades and cutting system.

In any embodiment, or permutation, of cutting blades and number ofcutting blades in the inventive cutting system, any number of spiralpieces can be obtained per product. That is 2, 3, 4, 5, 6, 7, 8, 9, or10, or more than 10 spiral pieces may be cut from each product. Inanother embodiment any number or all of the cutting blades may betextured or crinkled to produce textured or crinkled cut surfaces on aspiral piece. Thus, in one embodiment every spiral piece cut from oneproduct may contain at least one crinkle-textured cut surface if everycutting blade in the cutting system has a crinkled surface edge. Howeverin another embodiment not every cutting blade in the cutting system hasa wavy, textured, or crinkled edge. Thus, in that instance, a singleproduct may be cut to yield smooth surface spiral pieces as well ascrinkle-cut spiral pieces.

By “product” is meant any vegetable or fruit or wood. A vegetable thatmay be cut into 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10 spiralpieces that may have smooth or textured/crinkled surfaces, includes, butis not limited to, any tuberous vegetable, beets, turnips, radish,leeks, or any root vegetable. In one embodiment, a tuber is a potato,sweet potato, carrot, cassava, swede, or yam. A fruit that may be cutinto 2, 3, 4, 5, 6, 7, 8, 9, 10, or more than 10 spiral pieces that mayhave smooth or textured/crinkled surfaces, includes, but is not limitedto, apples, squash, bell peppers, pumpkin, zucchini, cucumber, mangos,and plantains. A vegetable or fruit when it is processed and cutaccording to the methods disclosed herein does not necessarily have tobe whole. That is, chunks or cut pieces of a vegetable may be pumpedinto the cutting system and those chunks or pieces subsequently cut withcutting blades to produce spiral pieces or spiral fragments.

The present invention in particular encompasses a new french fry that isspiral-cut and which may have smooth or crinkled surfaces. See, forinstance, the spiral potato pieces shown in FIG. 9. The types ofspiral-cut potato wedges are a new line of edible products, and can bemade in different sizes or textured or smooth surfaces according to thepresent invention. Thus one embodiment of the present invention is apackage containing multiple spiral-cut potato pieces or wedges whereinsubstantially all the spiral cut pieces or wedges are about the same orsimilar size to each other. In another embodiment of the presentinvention is a package containing multiple spiral-cut potato pieces orwedges wherein many of the spiral cut pieces or wedges are about thesame or similar size to each other. A “package” may be a bag of the sortused to hold chips, or an open holder such as to hold fast-food frenchfries, or any such containment structure or vessel. In any of theseembodiments, one or more or all of the spiral cut potato pieces orwedges in a package may have a crinkle-cut surface. In anotherembodiment, the spiral cut potato pieces or wedges in the package may beraw or may be cooked, such as fried, roasted, or oven-baked.Accordingly, one embodiment of the present invention is a collection ofspiral-cut potato pieces that are raw, a collection of spiral-cut potatopieces that are fried, or a collection of spiral-cut potato pieces thatare oven-baked, or a collection of spiral-cut potato pieces that areroasted, wherein the pieces have smooth surfaces or have a crinkle-cutsurface. By “smooth” surface is meant a spiral cut product that has beencut with a cutting blade that has a flat, untextured, surface and edge.By “crinkle-cut” is meant a spiral cut product that has been cut with acutting blade that has a crinkled or wavy surface and edge, such asthose shown in FIG. 10. In a further embodiment, the spiral-cut potatowedges may be further processed or seasoned, such as to produce batteredor beer battered spiral-cut fried or oven-baked potato wedges.

Pieces of wood may also be cut into 2, 3, 4, 5, 6, 7, 8, 9, 10, or morethan 10 spiral pieces that may have smooth or textured/crinkledsurfaces. Softwoods could be cut according to the present invention, forinstance. Examples of softwood include but are not limited to pine,redwood, fir, cedar, and larch. Other materials may be cut according tothe present invention too, such as polystyrene, foam, solid paper pulpmaterials, and plastics.

Other features and advantages of the invention will become more apparentfrom the following detailed description, taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a schematic diagram depicting a hydraulic cutting system of atype utilizing a rotatably driven knife fixture constructed inaccordance with the present invention;

FIG. 2 is an enlarged perspective view illustrating a drive motor andcog belt for rotatably driving the knife fixture of FIG. 1;

FIG. 3 is an exploded perspective view showing rotatable mounting of theknife fixture within a rotary bearing unit;

FIG. 4 is a front side perspective view of one cutting blade carried bya ring-shaped blade holder in accordance with one preferred form of theinvention;

FIG. 5 is a front side perspective view of a pair of cutting bladescarried respectively by a corresponding pair of blade holders inaccordance with one alternative preferred form of the invention;

FIG. 6 is a front side perspective view of a knife fixture includingthree cutting blades respectively supported by three blade holders inaccordance with a further alternative preferred form of the invention;

FIG. 7 is a front side perspective view of four cutting blades carriedrespectively by four blade holders in accordance with anotheralternative preferred form of the invention;

FIG. 8 is a drawing similar to FIG. 7 but showing four corrugated orcrinkle cut knife blades;

FIG. 9 is a drawing showing a spiral piece or wedge cut with the crinklecut knife blades shown in FIG. 8;

FIG. 10 is a drawing of an exemplary cutting blade designed to havetextured or wavy or crinkled surfaces and edges so as to produce spiralpieces or wedges that have similarly textured, wavy, or crinkled cutsurfaces;

FIG. 11 is an enlarged front side perspective view taken about thecircle 11 in FIG. 7, further illustrating the inclined mounting surfacein the blade holder;

FIG. 12 is a front side perspective view of an embodiment of a pair ofcutting blades carried by a ring-shaped blade holder; and

FIG. 13 is a front side perspective view of an embodiment of threecutting blades carried by a ring-shaped blade holder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention relates generally to devices and methods for cutting foodproducts, such as vegetable products, and particularly such as rawpotatoes and the like, into spiral or helical shaped pieces, whose cutsurfaces may be patterned by the design of knife blades, such as tocreate “crinkle-cut” spiral or helical pieces.

More particularly, this invention relates to a rotatably driven knifefixture having a selected number of knife blades adapted to cut a rawpotato or the like into generally spiral shaped pieces.

As shown in the exemplary drawings, a hydraulic cutting system comprisesa conventional so-called water knife fixture referred to generally inFIG. 1 by the reference numeral 10 for cutting vegetable products suchas whole potatoes 12 into spiral shaped pieces 14 for subsequentprocessing. The present invention comprises a rotary driven knifefixture 10 (FIGS. 2-7) for installation into the cutting system and forrotatable driving by means of a drive motor 11 or the like. The knifefixture 10 includes at least one rotatably driven cutting blade 16(FIGS. 2-4) for cutting the product into a pair of generally spiralshaped pieces 14 of the same or similar size and shape. In alternativeembodiments, the single cutting blade 16 can be combined with a secondcutting blade 17 (FIG. 5) to cut the product into four spiral shapedpieces, with a third cutting blade 18 (FIG. 6) to cut the product intosix spiral shaped pieces, or with a fourth cutting blade 19 (FIG. 7) tocut the product into eight spiral shaped pieces. Indeed, any number ofcutting blades can be used for subdividing the product into twice thenumber of spiral shaped pieces of substantially similar size and shape.

FIG. 1 shows the cutting system in the form of a hydraulic cuttingsystem comprising a tank 78 or the like for receiving a supply ofvegetable products, such as the illustrative raw whole potatoes 12 in apeeled or unpeeled state. Alternatively, these potatoes 12 can comprisehalves or pieces of whole potatoes, peeled or unpeeled. In one preferredform, these potatoes 12 comprise relatively small potatoes or potatopieces having a longitudinal length on the order of about 3 inches. Itis noted, however, that actual potato size is unimportant, as long asthe potato has a diametric size to fit through the knife fixture.

As viewed in FIG. 1, the potatoes 12 are delivered via an inlet conduit30 to a pump 32 which propels the potatoes in single file relationwithin a propelling water stream or flume through a tubular deliveryconduit 34 into cutting engagement with the blades (not shown in FIG. 1)of the water knife fixture 10. In a typical hydraulic cutting system,the potatoes are propelled through the delivery conduit 34 at arelatively high velocity of about 25 feet per second (fps), or about1,500 feet per minute (fpm), to provide sufficient kinetic energywhereby each potato is propelled through the knife fixture 10 to produce(as will be described in more detail herein, per the blade pitch angle)the desired elongated spiral cut pieces 14. In this regard, the deliveryconduit 34 may include a centering alignment device (not shown) forsubstantially centering each potato 12 on a longitudinal centerline ofthe flow passage extending through the associated knife fixture 10, in amanner known to persons skilled in the art. The cut strips 14 travelthrough a short discharge conduit 36 to a conveyor 38 or the like whichtransports the cut strips 14 for further processing, such as blanching,drying, batter coating, parfrying, freezing, etc.

Persons skilled in the art will recognize and appreciate thatalternative form cutting systems may be used, to include, by way ofexample, mechanical cutting systems wherein the vegetable products suchas potatoes are mechanically delivered via a chute or hopper or the liketo the knife fixture 10. In either case, the knife fixture 10 is mountedalong a production path and is rotatably driven for engaging and cuttingthe incoming products into the desired spiral shaped pieces.

FIGS. 2-3 show installation of the illustrative knife fixture 10 into arotary bearing unit 20 in a position in-line with a production path forthe vegetable products such as the potatoes 12 (FIG. 1). In this regard,the illustrative knife fixture 10 comprises a generally ring-shapedblade holder 22 of generally annular or circular shape, and having across sectional area sufficient for providing a relatively stiff orsturdy structure capable of withstanding the rigors of a productionenvironment over an extended period of time. This blade holder 22 issecured as by means of clamp screws 23 or the like onto downstream orlower annular ring 21 or the like adapted in turn for affixation to thelower or downstream end of a rotatable bearing assembly 25 as by meansof screws 25′ or the like.

As shown in FIG. 3, the bearing assembly 25 is rotatably carried withina bushing 26 mounted as by means of screws 26′ or the like onto anupstream or upper side of the enlarged plate 27, which has an opening 13formed therein for in-line installation along the production flow path.A flange plate 28 overlies the bearing assembly 25 for sandwiching theassembly 25 against an internal shoulder 29 within the bushing 26. Adriven ring BO is mounted in turn as by means of screws 30′ onto thebearing assembly 25 for rotation therewith.

The driven ring 30 of the rotary bearing unit 20 includes acircumferential array of detents 41 for registry with teeth 42 of acog-type drive belt 43 (FIG. 2). This drive belt 43 is in turn reevedabout a drive gear 44 on an output shaft 45 of the drive motor 11 (FIG.2). Accordingly, the drive motor 11 positively drives the driven ring 30and associated bearing assembly 25 secured thereto at a known speed,preferably on the order of about 6,000 rpm in the case of theillustrative hydraulic cutting system, for correspondingly rotatablydriving the knife fixture 10 at the same rotational speed. Importantly,the cog-type drive belt 43 beneficially insures constant-speed rotatabledriving of the knife fixture 10 notwithstanding periodic impactengagement of the water-propelled potatoes therewith.

In one preferred configuration as viewed in FIGS. 2-4, a single cuttingblade 16 is used to cut each incoming vegetable product such as a potato12 into two separate, generally spiral shaped pieces 14 (FIG. 1) ofsimilar size and shape. The cutting blade 16 is shown with a sharpenedcutting edge 16′ along one side thereof. Since the cutting blade 16 istwisted generally at a radial center, or a longitudinal centerline oraxis of the hydraulic flow path, two cutting edges 16′ are defined toextend radially outwardly in opposite directions, and in opposite-facingcircumferential directions. In other words, a first portion 16A of thecutting blade 16 that is adjacent to the blade holder 22 has a cuttingedge 16′ with a different pitch angle than that of a second portion 16Bof the cutting blade 16 that is located further from the blade holder 22than the first portion 16A. A pair of clamp screws 31 or the like aresecured through the respective opposite ends of the cutting blade 16 toseat the cutting blade within a shallow recess formed at an appropriatepitch angle.

More specifically, the specific pitch angle of the cutting blade 16 ateach specific point along its radial length is given by the formula:

Pitch Angle=ArcTan (2×Pi×Radius/Pitch Length)  (1)

For a total blade radius of 2 inches, and a pitch length of about 3inches, the clamp screws 31 secure the outermost radial ends of eachcutting blade 16 or 17 at a pitch angle of about 76.6° to the axialblade centerline. It will be understood, however, that the specificpitch angle is directly proportional to the radial point along theblade, whereby the pitch angle increases from the radial center, and itis this pitch angle that determines the spiral shape of the cut product.

If more spiral shaped pieces 14 are desired from each potato 12, morecutting blades are used recognizing that each of the cutting blades cutsthe incoming product in two, and thereby produces twice the number ofspiral shaped pieces in comparison with the number of cutting bladesused. Importantly, the cutting blades are arranged in succession atcontrolled angles to obtain similar or virtually identical cut spiralshaped pieces.

More particularly, in one preferred form as viewed in FIG. 5, twocutting blades 16 and 17 are supported by separate blade holders 22 and22′ in a stack on the associated annular ring 21, as by means ofelongated screws 23. That is, aligned screw ports are formed in thesecond blade holder 22′ at the appropriate positions for receiving theelongated screws 23 used to fasten the drive rings 22, 22′ and theunderlying annular ring 21 together for concurrent rotation.

The two cutting blades 16 and 17 are generally identical to each to eachother, to include a twisted shape generally at a longitudinal centeraxis thereof and extending radially outwardly in opposite directions forseated engagement as by means of clamp screws 31 or the like at theselected pitch angle. Using formula (1) above for the specific pitchangle of each blade 16 or 17 along its radial length, and wherein thetotal blade radius is 2 inches and the pitch length is 3 inches, theclamp screws 31 secure the outermost radial ends of each cutting blade16 or 17 at a pitch angle of about 76.6°. In this respect, FIG. 11 morespecifically illustrates the inclined mounting surface in the bladeholder 22 at the point where the clamp screws 31 secure the cuttingblade 16 to the blade holder 22.

In addition, when the two cutting blades 16 and 17 are rotated at about6,000 revolutions per minute (rpm), to advance each product to be cutalong the hydraulic flow path at a velocity of about 25 feet per second(fps), the two cutting blades 16 and 17 both cut the incoming productinto two pieces, for a total of four spiral shaped pieces 14 of similaror identical shape. With a pitch length of about 3 inches potato travelfor each cutting blade revolution, and with each of the blade holders22, 22′ having an axial dimension of about 0.5 inch, the angle Θ (theta)separating each of the supported cutting blades is given by the formula:

Θ=T/P (axial dimension of each blade holder/pitch length)×360°+360°/N(number of cut pieces).  (2)

In the case of the two cutting blades 16, 17 adapted to cut eachincoming product into four generally identical spiral shaped pieces, theangle 1=150°.

FIGS. 6 and 7 illustrate two exemplary alternative preferred forms ofthe invention, wherein three cutting blades 16, 17 and 18 are separatelysupported by a stack of three ring-shaped blade holders 22, 22′, and 22″for cutting each incoming product into a total of six spiral shapedpieces (FIG. 6), and also wherein four cutting blades 16, 17, 18 and 19are separately supported by a stack of four ring-shaped blade holders22, 22′, 22″, and 22′″ (FIG. 7) for cutting each incoming product into atotal of eight spiral shaped pieces. In the examples of FIGS. 6 and 7,formula (2) is followed to determine the angular setting of each cuttingblade in succession in order to form the multiple spiral shaped piecesof identical or similar shapes. In FIG. 6, the cutting blades are set atsuccessive angles of about 120° to cut products per U.S. Patent D640,036which is incorporated by reference herein, whereas in FIG. 7, thecutting blades are set at successive angles of about 105°. In each case,clamp screws 31 are used to seat each of cutting blades at the selectedpitch angle within the recess formed in the associated blade holder.Similarly, screws 23 or the like are fitted and secured through alignedports formed in the stacked blade holders for securing them together forrotation with the bearing assembly 25.

Persons skilled in the art will understand and appreciate, of course,that virtually any number of cutting blades can be used, with theformula (2) determining the angular spacings of the multiple cuttingblades in succession. For example, when five cutting blades are used, atotal of ten spiral shaped pieces are formed; following formula (2), thesuccessive cutting blade angular spacings would be about 96°. Similarly,when six cutting blades are used, a total of twelve spiral shaped piecesare formed; following formula (2), the successive cutting blade angularspacings would be about 90°. Persons skilled in the art will alsoappreciate that when three or more cutting blades are used, the formula(2) determines that angular spacings of the blades as a group, but thateach of the blades need only be set at one of the angular positions;that is, the blades do not need to be set at a regular lag interval, solong as one of the blades in the group is set at each one of the angularpositions.

Alternately, it will be understood that other forms of the blade holdersand the related interconnection means can be employed, such as theformation of steps including interengaging tabs and slots in therespective blade holders to insure the desired angular position of thecutting blades and concurrent rotation thereof.

In an alternative preferred form, the present invention encompasses anew french fry that is spiral-cut and which may have corrugated orcrinkled surfaces. See, for instance, the spiral potato pieces 14′ shownin FIG. 9. The types of spiral-cut potato wedges are a new line ofedible products, and can be made in different sizes or textured surfacesaccording to the present invention. Thus one embodiment of the presentinvention is a package containing multiple spiral-cut potato pieces orwedges 14′ wherein substantially all the spiral cut pieces or wedges areabout the same or similar size to each other. In another embodiment ofthe present invention is a package containing multiple spiral-cut potatopieces or wedges 14′ wherein many of the spiral cut pieces or wedges areabout the same or similar size to each other. A “package” may be a bagof the sort used to hold chips, or an open holder such as to holdfast-food french fries, or any such containment structure or vessel. Inany of these embodiments, one or more or all of the spiral cut potatopieces or wedges in a package may have a crinkle-cut surface. In anotherembodiment, the spiral cut potato pieces or wedges in the package may beraw or may be cooked, such as fried, roasted, or oven-baked.

Accordingly, one embodiment of the present invention is a collection ofspiral-cut potato pieces that are raw, a collection of spiral-cut potatopieces that are fried, or a collection of spiral-cut potato pieces thatare oven-baked, or a collection of spiral-cut potato pieces that areroasted, wherein the pieces have smooth surfaces or have a crinkle-cutsurface. By “smooth” surface is meant a spiral cut product that has beencut with a cutting blade 16, 17, 18 or 19 that has a flat, untextured,surface and edge, as viewed in FIGS. 4-7. By “crinkle-cut” is meant aspiral cut product that has been cut using a modified knife fixture 11′with a cutting blade 16″, 17″, 18″, or 19″ that has a crinkled or wavysurface and edge 16″, 17″, 18″, or 19′, such as those shown in FIG. 8.In a further embodiment, the spiral-cut potato wedges may be furtherprocessed or seasoned, such as to produce battered or beer batteredspiral-cut fried or oven-baked potato wedges.

It will be understood, of course, that the modified knife fixture 11′shown in FIG. 8 can be equipped with one or more of the cutting knivesof a corrugated and crinkle-cut configuration, as per any one of theknife blade embodiments depicted in FIGS. 4-7. Indeed, more than foursuch knife blades can be used, if more than 8 spiral-cut wedges aredesired. It will also be recognized and understood that different sizecorrugations or crinkle-cut configurations can be used for the variousknife blades, such as illustrated in FIG. 10 with respect to thecorrugated knife blade 16″, and the associated cutting edge 16″'.

A variety of modifications and improvements in and to the rotary knifefixture 10 of the present invention will be apparent to those personsskilled in the art. As one example, persons skilled in the art willunderstand that each of the twisted cutting blades as shown anddescribed herein can be replaced by a pair of individual blades aligneddiametrically with each other and having a pitch angle as defined byformula (1), but otherwise unconnected at the axial centerline of theflow path. For instance, in FIG. 12, the blade 16 of FIG. 4 has beenreplaced by a pair of individual blades 116 aligned diametrically butotherwise unconnected at the axial centerline of the flow path. As afurther alternative, the blades do not need to be aligned diametrically,but an odd number of unconnected blades, such as three blades 216 shownin FIG. 13, can be used in the event that an odd number of product cutsis desired. Accordingly, no limitation on the invention is intended byway of the foregoing description and accompanying drawings, except asset forth in the appended claims.

What is claimed is:
 1. A knife fixture for cutting food products, thefixture comprising: a blade holder; and at least one cutting blade witha cutting edge, each of the at least one cutting blade extending inwardfrom the blade holder and being twisted such that the cutting edge has apitch angle that varies along the cutting blade.
 2. The knife fixture ofclaim 1, wherein the blade holder forms an opening surrounding a centralaxis and each of the at least one cutting blade extends from the bladeholder and across the opening.
 3. The knife fixture of claim 2, whereinthe blade holder includes a plurality of angled recesses, the at leastone cutting blade being secured within the plurality of angled recesses.4. The knife fixture of claim 3, wherein each of the at least onecutting blade is secured within the plurality of angled recesses at eachend of the cutting blade.
 5. The knife fixture of claim 2, wherein theblade holder is rotatable about the central axis.
 6. The knife fixtureof claim 2, wherein the at least one cutting blade is a plurality ofcutting blades.
 7. The knife fixture of claim 6, wherein the pluralityof cutting blades are unconnected at the central axis.
 8. The knifefixture of claim 7, wherein the plurality of cutting blades include apair of individual blades aligned with each other along a longitudinalaxis.
 9. A helically twisted piece of food product produced by the knifefixture of claim
 1. 10. The helically twisted piece of food product ofclaim 9, wherein the food product is a potato.
 11. A cutting system forcutting potatoes into multiple helically twisted pieces, comprising: ablade holder having a flow path therethrough; at least one cutting bladeoriented across the flow path, each of the at least one cutting bladehaving a sharpened edge, wherein an angle of the sharpened edgeincreases along a length of the cutting blade towards the blade holder.12. The system of claim 11, further comprising a drive motor configuredto rotatably drive the blade holder.
 13. The system of claim 11, whereinthe at least one cutting blade is a plurality of cutting blades.
 14. Thesystem of claim 13, wherein the plurality of cutting blades areunconnected at an axial centerline of the flow path.
 15. The system ofclaim 14, wherein the plurality of cutting blades include a pair ofindividual blades aligned with each other along a longitudinal axis. 16.The system of claim 13, further comprising a centering alignment deviceconfigured to center potatoes in the flow path for cutting engagementwith the plurality of cutting blades.
 17. A knife fixture for cuttingfood products, the knife fixture comprising: a blade holder forming anopening; and a blade carried by the blade holder, the blade having acutting edge and a longitudinal axis oriented across the opening, theblade being twisted about the longitudinal axis.
 18. The knife fixtureof claim 17, further comprising another blade having a cutting edge anda longitudinal axis oriented across the opening, the another blade beingtwisted about its longitudinal axis.
 19. The knife fixture of claim 18,wherein the longitudinal axis of the blade and the longitudinal axis ofthe another blade are aligned, and the blade and the another blade areunconnected at an axial centerline of the opening.
 20. The knife fixtureof claim 18, further comprising a third blade having a cutting edge anda longitudinal axis oriented across the opening, the third blade beingtwisted about its longitudinal axis, wherein the longitudinal axes ofthe blade, the another blade, and the third blade are not aligned.